There can be any mixture of node classes, including Group and Adornment. It automatically sorts the nodes within the layer so that each Group is behind its own children in this layer.

You may not apply any transforms to a NodeLayer; that is reserved to GoXam for future use.

System.Object
   System.Windows.DependencyObject
      System.Windows.UIElement
         System.Windows.FrameworkElement
            System.Windows.Controls.Panel
               Northwoods.GoXam.Layer
                  Northwoods.GoXam.NodeLayer

Reference